A blackbird or a dark-colored bird, particularly used in poetry and older texts; can refer to a specific type of bird.
From Old French 'merle,' from Latin 'merula.' The word is primarily literary and archaic in modern English, kept alive mainly in poetry and bird classifications.
Merle is the kind of word that survives in English mainly because poets loved it—it has a musical quality that 'blackbird' doesn't, which is why you see it in older literature and poetry, making it a perfect example of how certain words become 'literary' and fade from everyday speech.
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